CONCHODERMA 249 



According to Darwin (1851), L. australis is very closely related to L.fasciciilaris. In 

 my opinion, this latter species is distinct from all other species by the very different 

 carina, and it differs from L. australis by the presence of five filamentary appendages. 

 I think L. australis is most related to L. anatifera. 



The material contains individuals of all stages from pupae without any traces of 

 plates to fully grown specimens. From St. 8 a very large individual was taken with the 

 following measurements: length of capitulum 38mm., breadth 25 mm.; length of 

 peduncle 45 mm., breadth 9 mm. The largest individual described by Darwin has a 

 capitulum measuring 25-4 mm. in length, and that by Hoek (1883) 33-6 mm. in length. 

 Both are shorter than the Discovery specimen. The fully grown specimens agree well 

 with those figured by Weltner (1922, Fig. 2). For comparison a figure of a full-grown 

 specimen is given. It is of more interest to describe and figure the young stages, as they 

 are not exactly figured for all Lepas species. 



The first stage (Fig. 10, a) found is a pupa without any traces of plates. The 

 initial differentiation of the peduncle and the body has already taken place. The pre- 

 hensile antennae are very difficult to detach from the attachment surface. The shape of 

 the distal segments cannot be seen until the next stage. They have been studied and 

 figured previously. 



The second stage (Fig. 10, b) shows the further development of the peduncle, which 

 extends outside the Cypris valves. Under these the primordial valves of the capitulum 

 are formed. 



The third stage (Fig. 10, c) has a more developed peduncle, and is just leaving the 

 pupa stage, as the Cypris valves have been cast off. 



In the fourth stage (Fig. 10, d) the calcareous plates begin to appear under the 

 primordial valves. The same is to be seen in the next two stages (Fig. 10, e,f). By 

 development of these plates the primordial valves of the scuta are moved a little from the 

 occludent margin, a feature also stated for L. hillii (Leach, 1818) (see Nilsson-Cantell, 

 1928, p. 15). In the carina the prongs begin to develop, but they are smaller in these 

 young stages than in the fully grown individual. The umbonal teeth in the scuta are to 

 be seen already in the young stages here figured. This does not agree with what Jennings 

 (19 1 5, p. 289) found in young specimens of the same species. He found only " an incurving 

 at the umbo of either scutum". Possibly there is some variation in this character. 

 Finally it must be noted that there exists an individual variation in the size. Young 

 stages are sometimes found to be larger than more mature stages. 



Genus Conchoderma, Offers, 18 14 

 Conchoderma auritum (Linne, 1767). (Plate I, figs, i, 2, 3.) 



For synonymy see Nilsson-Cantell, 1921, Zool. Bidrag Uppsala, vn, p. 240. 



24. ii. 25. South Georgia. From Blue whale, ?. 22-58 m. No. 46. Two small specimens on 

 Coronula reginae. 



27. xi. 25. South Shetland Islands. From Sperm whale, S. Many specimens from teeth. 



4-2 



