504 PROCEEDINGS OF THE ACADEMY OF [Dec, 



depressed. Lateral margin on the side of the fixed finger is acute 

 a nd crenulated, the opposite edge being less acute and apparently 

 smooth. The palm is convex in the middle, a little concave towards 

 the crenulated margin. There is a submedian row of three small 

 tubercles on the distal half. The fixed finger is quite slender and 

 shorter than the palm. 



Measurements (in Millimeters) . 



a. 

 b. 



About 65 feet below the base of the Pecten bed at Tower N, 

 Culebra Cut. 



This species, one of the largest Callianassas, is rather abundant, 

 represented in the collection by ten chelae and some fragments. 

 Named in honor of Professor William B. Scott. It is evidently what 

 Herr Toula figured as Krabbenscheren, I.e., p. 512, Taf. XXX, 

 fig- 14. 



In a few specimens the hand is longer, length of palm 30, width 

 24 mm. 



In the Gabb collection from Costa Rica there is an imperfect 

 hand evidently referable to the same species. 



Volvulella micratracta n. sp. Text fig. 1. 



Bulla (Volvula) cf. ozytata Bush, Toula, I.e., p. 709, pi. 28, fig. 4, 1909. 



The shell resembles V. minuta Bush, from which it differs by the 

 noticeably longer posterior spine-like extension and more swollen 

 shape. The spiral sculpture is decidedly stronger, 

 consisting of distinct, continuous, widely spaced 

 grooves, of which three are at the anterior and two 

 at the posterior end. On the convex portion there 

 is some appearance of very shallow longitudinal 

 plication. There is a narrow umbilical slit. 

 Length 1.5, cliam. 0.7 mm. 



The type from Gatun is probably conspecific 



with a series of five specimens from Monkey River, 



British Honduras. These are larger, up to 2 mm. 



Fig. 1. long, and have more of the distinct grooves at the ends. 



They were found in mud brought up on an anchor. 



V. oxytata is a much more cylindrical species. 



