72 Records of the Indian Museum. [Vol. XIX, 



vSubgen. Subtagelus, nov. 



1851. Macha divisus, Spenglcr, Gray, Cat. Brit. Mits., \ll, p. 160. 

 1854. Tageltis (pars), Gray, Ann. Mag. Nat. Hist. (2) XIV, p. 24. 

 1874. Solecitrtiis bideiis, Reeve, Conch. Icon., XIX, fig". 35. 

 1887. Tageliis divisits. Spengler, Clessin, Martini-Chemnitz, Condi. 

 Cab., XI {Solenaced), p. 79- 



Animal. Bod}' similar to Tagelus. Mantle lobes strongly 

 muscular. Pedal aperture resembling that of Taf^elus. Cruciform 

 muscle a simple broad transverse band. Anterior adductor muscle 

 large and simple (not divided). Posterior adductor muscle large and 

 triangular. Foot comparatively large, deep and muscular, protrud- 

 ing obliquely downward and forward. Protractor pedis muscle 

 well-developed. Retractor pedis anterior and posterior muscles 

 short. Strongly developed elevator muscles. Pyloric stomach not 

 produced posteriorly be3^ond the origin of the coecum. 



The above diagnostic characters, drawn from the anatomical 

 description of Bloomer (15), clearly shows that the present animal 

 is more primitive than the members of the genus Tageliis. The 

 undivided anterior adductor muscle and the simple band-like cruci- 

 form muscle may be cited as evidence for the above conclusion. 

 It may also be suggested that the present subgenus (which might 

 almost be considered a genus) is closely connected to the ancestral 

 form which has given origin to Tagelus on the one hand and to the 

 type of Psammobiidae on the other. 



Conclusion. 



Although the little knowledge we had on the soft parts of the 

 members of the Solenidae has been greatly enhanced by the ana- 

 tomical researches of Bloomer, supplemented by my own study on 

 the small collection of the Zoological Survey of India, we are as yet 

 not in a position to discuss and arrive at a definite conclusion 

 regarding the phylogenetic question of the family, unless more 

 material comes into the hands of malacologists to be worked out 

 by them than is the case at present. The relation between the 

 three subfamilies is still obscure, but they seem to form fairly 

 natural and definite groups taken by themselves. The presence of 

 a short stout foot v/ith a fiat disc-like anterior end, and the absence 

 of a cruciform muscle in Novaculina point to the comparatively 

 primitive nature of the animal ; the non-plicate gills have no taxo- 

 nomic value more than as specific or subgeneric characters as 

 shown by Ridewood (pp. 16 1-2). The animal is, however, other- 

 wise specialised, and might be considered to have early separated 

 from the ancestral stock — perhaps earlier than the appearance of 

 the ancestral forms of the other two subfamilies. 



The great width of the body from side to side seen in Nova- 

 culina, certainly a primitive character again, has been retained in the 

 ancestral forms of Solecurtinae and has been handed down to its 

 members. This ancestral type of Solecurtinae must have acquired 

 the peculiar connection between the intestine and coecum of the 



