98 Natural History Bulletin. 



A small crab belonging to the genus Scsarnia was very 

 abundant on the pilings of an old wharf and on the sprawling 

 roots of the mangroves. The carapace is an oblong square, 

 wider in front, and with straight lateral and anterior margins 

 the latter being suddenly deflected between the widelv sepa- 

 rated eyes. The rather small chelae have bright red fin- 

 gers, and are haired on their external surfaces. A large num- 

 ber of specimens were secured, but they were all females. 



Around the spreading aquatic roots of the mangroves a 

 large assemblage of mollusks finds a secure and congenial 

 abiding place. Ax low tide our conchologists, Messrs. Drew 

 and Rogers, reaped a rich harvest by exploring the mangrove 

 swamp in one of the boats. The sprawling roots were then 

 above water, and were fairly bristling in places with mollusca 

 of many kinds. Among the gasteropods the following genera 

 were represented: Miircx, JVatica. jVen'ta, Cerithinni, Littor- 

 iiia, Potamides, Fissiirelhu and Bulla. 



The Lamellibranchiata were verv abundant in individuals, 

 although the species were not numerous. Area noes and A. 

 transversa were secured in quantities. MeJeagrina melcagris 

 formed large clumps of shells attached to the mangrove roots. 

 We could not learn that they were ever collected by the 

 natives, or that pearls were found in them. h. xQ.\-y fine Pinna 

 was abundant with the costce ornamented with rows of long 

 tubular spines. A species of Asaphis was secured which has 

 the umbo colored a delicate pink. 



The most abundant echinoderm found here was Toxopiiciis- 

 tcs variegatits, which furnished ample material for our students 

 to undertake a careful study of the echinoid anatomy. Micro- 

 scopes could be used to advantage while our vessel was float- 

 ing on the quiet waters of the bay, and the cabin-top proved 

 as good a laboratory table as could have been devised. 

 Arhacea ■puiictiilata was the only other echinoid found in 

 abundance. 



Several species of serpent-stars were found, but these forms 

 seem to prefer purer water than that of this bay. 



A few corals of the reef-building species were collected at 



