1907 



XATriJAI. SriF.NCES OF PHir.ADKI.l'iriA. 



409 



paces of crabs, while Mcnalasnid has been t'ouiid uKiiiily on sea-urdiin 

 spines and upon otlier cirripo(h>s. 



Megalasina carinodcutaliDn Weltner' was describecl from a single 

 example, and derived its name from the projection or tooth on the 

 roof of the carina. Tliis ]:)rojection, however, may very likely be patho- 

 logic, consequent upon an injury at the end of th(> carina when half 

 iirown. 



CdMPAUISOX OK M. IJKLLU.M AND M. MIXUS. 



.1/. helium (Pils.)' is closely related to M. minus Annandale.''' The 

 receipt of specimens of tlie latter, which 1 owe to the courtesy of Dr. N. 

 Annandalc, of the Indian Museum, enables me to compare the two 

 species more thorougiily tluui has hitherto been possible^ since the 



Fip;. 1. — Megaliisma minus Annaiid. 

 a, lateral, and b, ^•entral view, X 7^. 

 po, margin of tlie peduncular orifice. 



Fig. 2. — M. helium Pils. a, lateral, and 

 b, ventral view, X 4. u, umbo of the 

 scutum. 



published figures show onh' the external aspect of the capitulum, and 

 the internal features have not been described or figured. 



Megalasnm minus and M. helium are alike in' general shape and in 

 sculpture, but differ in size and in various details of the scuta and 



' Silzungft-herichte der Gesellschaft naturforschender Freunde zu Berlin, Jahrg. 

 1891. p. 84. 



* PftcUasma bellum Pilsbry, Bulletin of the Bureau of Fisheries, XXVI, p. 183. 

 pi. IV, fig. 6 (June 29, 1907). This paper was prepared in 1905, hence before 

 I knew of the existence of .1/. minus. 



* Megalasmn striatum subsp. tninus .\nnandale, .1 tnials and Magazine of Natural 

 Historii, SOT. 7, XMT, p. 399 (April, 1906); Illu.strations of the Zoology of the 

 Royal Indian Marine Svu-\ev Ship Investigator, Entomostraca, pi. 1, fig. 8 (1907). 



