150 Records of the Indian Museum. [Vol. X, 



South of the estuaries of the Mahanaddi, north of which mud 

 prevails, the coast is sandy and the sand extends outwards from 

 the shore for some miles. Off the northern part of this coast, in 

 from 15 to 30 fathoms of water, there are areas in which the 

 sea-bottom is coated with a recent conglomerate of sand and 

 partially dissolved shells,^ while in the southern part solid masses 

 are produced at about the same depth by the growth of gregari- 

 ous gastropods and stony sponges.'^ These harder areas are, how- 

 ever, restricted to water which, although shallow as compared 

 with the abysses of the central region of the Bay of Bengal, is 

 deep as compared with the strictly marginal zone, from which the 

 species to be considered here were obtained. 



The sponges described below are all encrusting species, de- 

 pendent, therefore, for their existence on comparative!)^ hard areas 

 on which to spread. These areas they find on the surface of the 

 shells of oysters and mussels. 



The general absence of algae of any considerable size from the 

 Indian coast north of Palk Straits is one of its most striking 

 biological features ; it is one that naturally restricts the space 

 suitable for the growth of siiall encrusting sponges, which in other 

 seas are frequently found on the stems and fronds of seaweeds. 



A . — Sponges from Madras Harbour. 



The stonework of Madras harbour affords a support for large 

 numbers of mussels {My tikis latus, Lam.) which in their turn are 

 usually coated with various encrusting organisms. During a recent 

 visit to Madras I was indebted to the assistance of Prof. K. Ramun- 

 ni Menon of the Presidency College of that city in obtaining a large 

 supply of these mussels in a living condition. The majority of them 

 bore on their surface, mingled with compound ascidians, branching 

 Cheilostomatous polyzoa, barnacles (Balanus amphitrite), etc., 

 specimens of one or more of the sponges here described. 



The largest shell measures 11 cm. in length and 5' 6 cm. in 

 breadth. 



The list of the encrusting sponges found on the mussel-shells 

 is as follows : — 



Family Desmaciodonidae. 



Mycale aegagropila (Johnston) var. militaris, nov. 

 Mycale inytilorum^ sp. nov. 

 Mycale inadraspaiana, sp. nov. 

 Lissodendoryx balanophilus, sp. nov. 



In addition to these encrusting forms a small and poorly 

 developed specimen of the widely distributed and well characterized 



1 Jenkins, Rec. Ind. Mas. VII, p. 51 (1912). 

 ''■ Annandale, ibid., VI, p. 47 (1911). 



