880 MR. W. WOODLAND ON THE [NoV. 27, 



of the supeiior maxillaiy aiid the small size of the mandibular 

 may perhaps be coi-related with the general conformation of the 

 skull — the elongated snout, probably used in "grazing" along 

 the sea-bottom, rendering the movements of the lower jaw of 

 little importance. In the dissection of the right orbit there is 

 cleai'ly observable a. large ganglionic mass (G) in connection with 

 the second and third roots of the fifth and seventh, and from 

 this there arise numerous small nerves supplying the muscles in 

 front of the spiracle and elsewhere. 



From the most posterior root of the three by which the fifth 

 and seventh nerves originate, thtire early arises the most charac- 

 teristic division of the facial nerve, viz. that which bifurcates 

 over the spiraculai- cleft. The prespiracular branch is small but 

 obvious ; the postspiracular is large, and just below the spiracle 

 divides as usual into the internal mandibular branch (chorda 

 tympani), which, as shown in fig. 17 (PI. LXI.), extends a long- 

 distance anteriorly under the orbit, and the external mandibular. 



According to the above provisional identification of the various 

 branches of the trigeminal and facialis, fibres of the seventh nerve 

 occur in both the anterior and posterior of the three roots. 



The disposition of the occipito-spinal nerves of C. calceus is 

 represented in fig. 14 (PI. LX.). As shown, two nerves originate, 

 ventrally to the vagus, in front of the spinal nerve corresponding 

 to the fii'st vertebra (the first spinal). This statement is con- 

 trary to that of Fiirbringer ^°, who provides figures of a longi- 

 tudinal section of the hind part of the skull of C. calceus in 

 which four such occipital nerves are shown, and of the occipito- 

 spinal nerves of C. granulosus in which the presence of four is 

 also implied. My dissection of these nerves was from the ventral 

 surface and was carefully made ; I could not, however, observe 

 more than two occipito-spinal nerves, as shown. These join with 

 the first two spinal nerves to form a single ti'unk which after- 

 wards divides into two branches, one forming a constituent of the 

 brachial plexus, and the other supplying the muscles of the lower 

 jaw. Spinal nerves 3-12 share in the formation of the brachial 

 plexus. The vagus has, in addition to the branchial, visceral and 

 lateral-line branches, two small ones, arising respectively from 

 the main trunk (just in front of and dorsal to the visceral) and 

 from the lateral-line branch near its origin, which run to dorsal 

 muscles more or less parallel with the vertebral column. I did 

 not determine the exact number of spinal nerves forming the 

 pelvic plexus, but I may state that I counted seven. 



Remarks on the Skeleton. 



Gegenbaur has supplied a full account of the head-skeleton of 

 C. calceujS in the woi-k before referred to "*, and I have very little to 

 add to his account. In the lateral view of the skull provided by 

 Gegenbaur (Taf . xii.), the extremely large, slightly-curved process 

 situated anteriorly on the upper edge of the upper jaw is not at 



