26 Records of the Indian Museum. [Vol. VII, 



Tomopaguropsis lanata^ Alcock. 



Tomopaguropsis lanata, Alcock, 1905, p. 137, pi. xiii, fig. 4. 



A single male was obtained at St. 391 in a stiell belonging 

 to the genus Pleurotoma. 



Sympagurus arcuatus, Milne-Edwards and Bouvier, 

 var. monstrosus, Alcock. 



Sympagurus arcuatus var. monstrosus , Alcock, 1905, p. 104, pi. x, 



fig. 5- 



Six specimens in Cancellaria cretacea, Smith, Pleurotoma sp. 

 and in other gastropod molluscs, were taken at St. 391. The 

 majority of the shells are encrusted by an anemone. 



Nematopagurus indicus, Alcock. 

 N ematopagurus indicus Alcock, 1905, p. 109^ pi. xii, fig. 4. 



Two specimens, a male and an ovigerous female obtained at 

 St. 391, are referred to this species. 



They agree with Alcock' s description and with the type 

 specimens in every particular except the eyes. These extend 

 only to the end of the proximal third of the ultimate segment 

 of the peduncle and are slightly shorter and very distinctly stouter 

 than in the t5^pe. We have been unable to find any other dis- 

 tinctions and we are convinced that the specimens are correctly 

 referred to this species. 



Bouvier (1900, pp. 194, 198, and 1894, p. 69, pi. xi, figs. 2 — 6) 

 has shown that in Sympagurus bicrisiaius, Milne-Edwards, and 

 S. gracilipes, Milne-Edwards^ there is considerable variation in 

 the size of the eye. In the case of the former species Bouvier 

 notes that in examples from comparatively shallow water the 

 cornea is as a rule more dilated than in those from greater depths ; 

 in S. gracilipes, however, he is of the opinion that no such 

 correlation exists. 



The present specimens were found in 237 fathoms and it is 

 interesting to note that in these examples the eyes are more 

 dilated than in the type specimens obtained at a depth of only 

 102 fathoms. The case, so far as the evidence goes, is therefore 

 precisely the reverse of that found in S. hicristatus ; but many 

 instances of a parallel development in one direction or the other 

 might be cited and it is no more difficult to believe that a shallow 

 water species migrating to greater depths would find it more 

 advantageous to increase its corneal area than that another 

 species also migrating in a similar manner should in this respect, 

 retrogress, finding that its other senses rendered ocular vision 

 a secondary consideration. 



The specimens were found in shells of N assay ia coromandelica, 

 Smith. 



