THE SKATE. 31 



coracoid : c.hy, ceratohyal : e.br. 3, third epi-branchial : e.hy, epi-hyal : 

 gl. I, gl. 2, gl. 3, anterior, middle, and posterior glenoid facets : 

 h.br. I, h.br. 3, h.br. 5, hypo-branchials of the first, third, and 

 fifth branchial arches : h.hy, hypo-hyal : hm, hyomandibular : hie, 

 commencement of haemal canal : it, iliac process : Ib. I, Ib. 2, Ib. 3, 

 Ib. 4, labial cartilages : mck, Meckel's cartilage or lower jaw : ms.pt, 

 mesopterygium.: mt.pt, metapterygium : ol, olfactory capsule : p.p' t 

 propterygium : p.pu, pre- pubic process : pt.qu, ptery go-quadrate 

 cartilage, or upper jaw : pu, pubic portion of hip girdle : r, rostrum : 

 r.c, rostral cartilage : sc, scapula : s.c.f, scapulo- coracoid fontanelle : 

 sp t spiracular cartilage : s.sc, supra-scapula. 



longitudinal axis of the centrum the cartilage intervening 

 between them is further strengthened by four radiating 

 plates of bone, which give rise to a cruciform figure in a 



FIG. ii. Raja nasuta. The last seven trunk vertebrae, and the 

 first ten caudal vertebras, viewed from the left side (nat. size). 



c, centra : cd. I, first caudal vertebra : d.r, dorsal root of spinal 

 nerve .: h.p, haemal process : h.s, haemal spine : i.n, inter-neural plate : 

 n.p, neural process : n.s, neural spine : r, rib : t, trunk of spinal 

 nerve : tr, transverse process : tr. 28, twenty-eighth (last) trunk 

 vertebra : v.r, ventral root of spinal nerve. 



transverse section of the centrum. The centra are seen to 

 continue backwards the ventral portion of the anterior 

 vertebral plate. 



6. The transverse processes (Figs, n and 12, #-), 

 backwardly directed rods of cartilage, which proceed one 

 from either side of the centrum, and continue backwards 

 the lateral ridges of the vertebral plate. 



