126 Natural History Bulletin. 



being so arranged that the}' form a tube just in front of the 

 rostrum pointing upward and a Httle forward. Tlie chel£e are 

 enormously enlarged, hard and expanded so as to form a com- 

 plete buckler when folded in front of the mouth-parts. 



Very few Anomura were found, the most abundant being 

 a hermit crab, Cenobita diogenes (Latr.) which occupied a 

 great variety of gastropod shells, although it seemed to 

 particularly favor a large Astraliiiiii. A ver}^ large hermit, 

 Eupaguriis. gnnnilatiis, was also common, and a truly gor- 

 geous object it was, with its brilliant vermilion chelas beauti- 

 fully ornamented with symmetricall}' disposed nodules. The 

 size of these crabs can be imagined when we say that they 

 sometimes occupied the shells of Strombiis gigas, one of the 

 largest mollusks of the West Indies. Petrolistes sex-spinostis 

 ( Gibbes) is the only other anomuran found at the Tortugas. 



The great disparity in numbers between the Brachyura, 

 or crabs, and the Macroura, or lobster-like forms, at this 

 station is indicated by the fact that not more than a half-dozen 

 .species of the latter were secured during our stay, while thirty- 

 odd species of the former have been identified. There were 

 four decapods, including one Alpliciis. One of the most 

 interesting of all the Crustacea is a Stomatopod, Gonodactylus 

 chiragra Latreille. much smaller than its familiar relative, and 

 with the chelai formed by a slender but exceedingly hard and 

 ivory-like distal joint without spines, which fits into a groove 

 on the upper surface of the joint below, being turned in an 

 exactly opposite direction from that taken by the ordinary 

 dactylopodite. 



Not the least attractive group included in the marine fauna 

 of the Tortugas is the Vermes, but unfortunately there was 

 no one in the party who was at all familiar with them. It 

 would be impossible, however, to see the many strange and 

 beautiful worms at this station without becoming interested 

 in their structure and admiring their exquisite coloring. ^ 



'Mr. 11. E. C. Ditzen had charge of the Vermes during the cruise, and 

 has located many of them in their proper genera, although the task was an 

 ainusually ditficult one, owing to the paucity of the literature at hand. 



