243 DISCOVERY REPORTS 



Caudal appendage single-jointed, conical, without bristles. The appendage is shorter 

 than the proximal segment of the protopodite. 



The complemental male is of the sack-like type without any traces of valves. The male 

 was situated in a very distinct pit on the inside of the scutum near the apex (Fig. 7, /)• 



Scalpellum africanum, Hoek, 1883. 



Hoek, 1883, Challeng. Rep. vni, p. 87. 

 Gruvel, 1905, Monogr. Cirrhip. p. 62. 



St. 6. i.ii. 26. Tristan da Cunha. 80-140 m., r. Gear DL. Six specimens on corals. 



Distribution. This species was described by Hoek (1883) from Tristan da Cunha, 

 the same place from which the Discovery material was taken. 



Discussion. Three closely related species, S. africanum, Hoek, 1883, S. triangulare, 

 Hoek, 1883, and S. botellinae, Barnard, 1924, have been described, and these have been 

 held by me to be, possibly, synonyms. The first two mentioned are grouped by Hoek in 

 two different sections of the genus, for he said that the rostrum is present in S. africanum 

 and absent in S. tria?igulare. As I have been able to study the types of both, it was 

 possible to find much external agreement between the two species, and at first I thought 

 that S. africanum represented a young individual of S. triangulare. But by studying the 

 internal parts I found certain differences, so it is, at present, inadvisable to unite them. 



The species S. botellinae is also close to S. africanum, even in the mouth-parts, but 

 other differences exist, for while the complemental male of S. botellinae has four valves, 

 that of S. africanum, as seen from this material, has none. 



Supplementary Description. One young stage (Fig. 8,y) with calcified plates was 

 studied. Of the lower latera the rostrum, the rostral and the carinal latera are developed 

 but rather small. Of the inframedian I was unable to find any trace. The primordial 

 plates are very distinct and of a peculiar perforated structure, as is also found in S. 

 eumitos, Barnard, 1924. In other species of Scalpellum I have found these holes to be 

 filled up. The tentacle-like process at the top of the capitulum is very distinct. On the 

 peduncle there were the four large scales. 



Female. The fully grown specimens were all covered by a thick hairy cuticle, which 

 had to be removed before one could study the valves. To the description of the capitular 

 valves nothing can be added to that given by Hoek. 



Scutum quadrangular with rather convex umbo and recurved apex. 



Tergum triangular with convex occludent margin and recurved apex. 



Carina regularly bent, with the umbo at the apex. Dorsal roof convex. Sides well 

 developed with wide areas in the upper part. 



Upper latiis quadrangular with the carinal margin shorter than the others, which are 

 nearly equal in length. 



Rostrum triangular with apical umbo. 



Rostral latus quadrangular with short basal margin. The plate wider than high. 



