Chthonicola, nov. gen. 



Char. gen.— Rostrum breve, a basi descendens, mandibuia superiore 

 ad apicem Iseve dentata, in lateribus corapressa. Tomia introrsum 

 curvatee, Ala concavae, primano primo perbrevi, tertio, quarto, 

 ąuinto et sexto longitudine Eeąualibus. Tarsi moderati. Digiti 

 breves, posticus medio brevior. Ungues anteriores magis quam 

 in " Antho" curvati. 



Gen. char.—BiM short, gradually descending from the base ; the 

 upper mandible sligbtly notched at the tip, compressed laterally ; 

 tomia curving inwards ; \vings concave ; the first primary very short, 

 the third, fourth, fifth and sixth nearly equal and the longest ; tail 

 slightly concave, and all the feathers of an equal length ; tarsi mcde- 

 rately long ; toes short, the hinder toe somewhat longer than the 

 middle one ; front claws more curved than in the genus Anthus. 



5. Desceiption of a new species of Amphioxus from Borneo. 

 By j. e. Gray, Esq., F.R.S., etc. etc. 



Capt. Sir Edward Belcher having most kindly sent to the British 

 Museum the various species of reptiles, \vorms, &c. in spirit \vhich 

 had been collected during the voyage of H. M. S. Samarang, I hasten 

 to lay before the Society the description of what appears to be a new 

 species of Lancelet (Branchiostoma, Costa = Amphioxus, Yarrell), 

 premising that I have sent a second specimen to Dr. Clarke, R.N., 

 of Haslar, who has kindly promised to send me some anatomical 

 details of it, which shall be communicated to the Society as soon as 

 they arrive. 



I may remark that the specimen from Borneo very much resembles 

 in size the specimen which Mr. Couch obligingly sent to me from 

 Cornwall, and, likę it, is more silvery and considerably larger than 

 numerous specimens I have received through the kindness of Dr. 

 Kolhker from Naples. This difFerence in colour may arise from the 

 Naples specimens having been placed in stronger spirits ; but it gives 

 the Comish and the Borneon specimens much more the resemblance 

 of Annelides, -vvhich generally have this metallic iridescent silvery 

 hue. 



The resemblance of the Borneon to the Comish specimen is so 

 striking, that it is very difficult to draw a distinction bet\yeen them 

 \vith neatness or brevity ; yet they appear to my eye sufficiently dif- 

 ferent to induce me to regard them as distinct species, which the 

 great geographical distance betvveen their habitats renders probable. 



Amphioxus Belcheri. — The Borneon Lancelet appears rather thicker 

 and more convex on the sides than Amph. lanceolatus, and the conves 

 ridge which occupies the place of the dorsal fin appears higher and 

 more closely divided by internal transverse septa than in that species, 

 and these septa appear more numerous. I have not been able to 

 observe any beards on the margiu of the mouth, which is thickened 

 and rounded ; but this may arise from the specimen not being in 

 good condition, especially in this part where it has been injured by 

 the spines of a Spattmgus which \vas in the šame bottle. 



No. CLXXI. — Prooeedings of the ZoologiCal Society. 



