120 Dr. W. T. Caiman on 



spinose. Four very small calcined valves are clearly visible 

 in some specimens, but in others no trace of these is to be 

 detected. 



Measurements. — Female (holotype). Length of capitulum 

 43 mm., breadth 36 mm., thickness 19 mm. ; length of 

 peduncle 48 mm., diameter 21 mm. 



Male. About 0*8 x 0*45 mm. 



Remarks. — A group of species within the section Arco- 

 scalpellum of Hoek is characterized by the great thickness 

 of the cartilaginous substance of the capitulum, so that the 

 calcareous valves are entirely or all but entirely concealed. 

 The group includes, in Oriental seas, S. alcockianum and 

 S. persona, Annandale, from both of which the species now 

 described is separated by the brevity of the caudal appendages 

 and by various small characters of the calcareous valves-, the 

 non-excavated margins of the terga being perhaps the most 

 important. In the Atlantic the most closely related species 

 is S. giganteum, Gruvel, which is distinguished by various 

 details of the capitular valves and by the truncate, almost 

 clavate, form of the short caudal appendages. From all 

 these species that now described appears to differ further in 

 the flattened parietes of the carina and in having no penis. 

 This last character is probably of great importance as a 

 specific distinction, although Pilsbry has stated that in 

 S. regium the penis may be present or absent (Bull. U.S. 

 Nat. Mus. lx. 1907, p. 28), or, in other words, the large 

 individuals of the species may be either hermaphrodite or 

 purely female *. 



The specific name is chosen in recognition of the part 

 taken by Mr. Walter Judd in obtaining for the Museum the 

 very interesting collection now described. 



Scalpellum {Scalpellum) persona, Annandale. 



Scalpellum ])erso?ia, Annandale, Jour. Straits Branch. Boy. Asiatic 

 Soc. No. 74, 1916, p. 295, pi. iv. fig. 3, pi. v. figs. 7, 8, pi. vi. 

 figs. 3-5. 



Locality.— Lai. 8° 46' S., long. 114° 44' E. (Java-Aus- 

 tralia), 400 fath. C./S. ' Recorder/ 8 g . 



Remarks. — The specimens agree well with the descriptions 



* Pilsbry implies that only one specimen of S. ret/turn was examined 

 by Hoek as to this character. There were at least six syntypes, but only 

 two now survive, and one of these is imperfect ; the other has no penis. 

 On the other hand, the holotype of S. regium, var. ovale (which, from 

 other characters, may possibly deserve specific rank), has a penis. 



