Saptashati

Shakti	Part of AUM	Guna	Resembling God
Tulja bhavani	A kara	Rajas	Brahma Sarasvati
Maha lakshmi	U kara	Satwa	Vishnu Laxmi
Renuka mata	Ma kara	Tamas	Maheshwara Parvati
Saptashringi mata	Ardha matra	Trigunateeta	Adi Shakti Adi Purusha

Saptashati has three main cycles or charitas with 3 principle deities presiding over each cycle.

1. One is Dasabhuja (10-handed) Mahakali,
2. Second is Ashtadasa Bhuja (18-handed) Mahalakshmi and the
3. last is Ashtabhuja (8-handed) Mahasaraswathi.

The samasti rupa Shakti is Chaturbhuja (4-handed) MahaLakshmi. Corresponding to these 4 deities, there are 4 shakta pitas in Maharashtra.

1. Ekaveera Devi of Mahurgad near Nanded district of Maharashtra corresponds to MahaKali of Prathama Charita.
2. Sapthashringi Devi having 18 hands at village Vani near Nashik corresponds to Mahalakshmi Madhyama Charita.
3. Bhavani Devi of Tuljapur (Tulja Bhavani who presented the khadga to Shivaji) corresponds to Maharaswathi of Uttama Charita.
4. The Mahalakshmi of Kolhapur corresponds to the Mula Chandi (Samasti Rupa of all 3 cosmic powers). This Mahalakshmi of Kolhapur is having 4 hands adorning with 

1. Bijapura Phala (a kind of sweet lime), 
2. Gaga (Mace),
3. Khetaka (shield),
4. Sura / Pana Paatra (a bowl) in her 4 hands.

At Saptashrungi, one can visit the Samadhi of Guru Matsyendranath of Natha Sampradaya. Here, there is a temple dedicated to Sage Markendeya. Everyday, the Sage Markendeya chants all the puranas in front of Sapthashringi Devi. And hence, here one of the 18 hands of devi is near one of her ears as if she is keen enough in listening to the Markendeya chanting the puranas.

These 4 shakta pitas are called “Saade Teen Sakti Pith” in Marati language. In local parlance,Maharashtrians call them as “Ambaa Maayi”. Even the word Mumbai is derived from “Maha Ambaa Aayi”. Aayi denotes the “Mother”. She is the Great Mother Mumba Devi.

Detailed Links of These four Goddess temples are

1. Mahalakshmi Temple at Kolhapur, 
2. Tulja Bhavani Temple at Tuljapur, 
3. Renuka Temple at Mahur (Matripur) and the
4. Sapatashrungi Temple of Vani.

Kundalini

According to Yoga shastras and Tantra shastras, Shakti is present in our body in the form of Kundalini. It is described as a female serpent which is sleeping in Muladhara Chakra turning it's body into three and half (3 1/2) circles. If it is activated with the help of Spiritual practices, it raises and passes to Sahasrara through Sushumna, a small passage in Spinal cord. The three and half folds of Kundalini are compared with the four forms of Shakti present in this list of Four Shakti peethas of Maharashtra.

https://www.google.com/search?site=imghp&tbm=isch&source=hp&biw=1280&bih=600&q=Three+and+a+half+Shakti+Peeth
http://www.youtube.com/results?search_query=Three+and+a+half+Shakti+Peeth