ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 61 



long cylindrical process, reaching with the point into the ventral recess 1 ), which is here situated far 

 backward, almost terminally (/.r'); on the dorsal side are seen the two same recesses 2 ) as in the Skate, 

 but of different size and extent, as well as the projecting lamella Rd' 3) borne by the skeleton; the 

 only new thing that does not seem to be represented in the Skate, is a strongly projecting part sup- 

 ported by the skeleton, da*), which part belongs to the ventral side; it corresponds to the porons, 

 spongy, firm dermal fold in the Skate, where, however, no skeleton is found. 



The Skeleton. Between the basale and the appendix-stem ( Metatarsien Moreau |Cuv., 

 Duvernoy]) there is a <?, bearing the last six rays, a b z without rays, a flat /? with s-shaped edges, 

 proximally connected with b ly and distally by means of a joint with the appendix-stem 5). This latter 

 is about (scarcely) twice as long as B -j- b l -|~ b 2 , and closely behind the two proximal articular sur- 

 faces for b 2 and t 3 it becomes flattened, and ends with a quite flat, thin-edged, hindmost rounded part; 

 corresponding to the great length of the terminal part, the uncalcified style ( une sorte de phalange 

 Moreau [etc.]) forms the greater part (about two thirds; in my figure it is a little too short); also here 

 is found, about at the middle of the medial edge, a thickened and somewhat calcified part. The 

 marginal cartilages are large, plate-shaped; the dorsal one reaches farthest forward, but behind it 

 ceases much before the ventral one; the dorsal cartilage sends forth into the interspace between the 

 terminal pieces a long, firmly calcified, s-shaped and pointed, blade-like process, bent in an undulating 

 way, and with sharp edges (Rd\ fig. 50). 



The terminal pieces are 5 (6), to which is still to be counted a covering piece 6 ). This (d) is 

 situated dorsally, is flatly rounded on the outer side, concave towards the terminal part, whose prox- 

 imal portion it covers; anteriorly it is curved in an oblique, half-moon-shaped manner, having the 

 lateral fore corner far drawn out; from this corner it shows an elevation running towards the medial 

 edge, and indicating the place of attachment of the M. dilatator; consequently the whole part before 

 this line is covered by the muscle. 7V?) has a broad line of attachment with the distal edge of the 

 dorsal marginal cartilage, but only touches the appendix-stem; outward it is somewhat flat, inward 

 concave; its lateral edge is convex, and somewhat indented; its distal end is attached to the appendix- 

 style by soft tissue, representing the cartilaginous bridge in the Skate. The piece Td 2 found in R. 

 bafis is wanting here. Tv is a long, slightly bent piece 8 ), provided with a short, hook-like point, and 

 having before a short articulation with the distal end of the ventral marginal cartilage, medially a 

 long connection with the appendix-style, reaching until the thickened and calcified place in this latter; 

 laterally it is for a rather long way connected with a bayonet-like Tv 2 9); this latter is connected with 

 the hindmost lateral edge of the ventral marginal cartilage by an oblique articulation , and distally it 



1) Petri etc. 

 *) Petri a la, alp. 

 Petri pr. 



4) Petri da. 



5) Petri, fig. 1 C, 61 , i 2 , r \ Moreau (= Cuvier-Duvernoy): Tibia, astragale, calcaueum; basale r= femur. 



6 ) Petri: sell' schuppenfSrmiger Knorpel , grossere Schuppenlamelle.; Moreau: Cartilage interne, no. 3, fig. 27, 

 1. c. p. 250. 



7) Petri: sck, likewise schuppenf. Knorpel , kleinere Schuppenlamelle p. 3121; Moreau: Cartilage externe, 110.2. 



8 ) Petri: si; Moreau: Cartilage no. 6 bis, cartilage en cuilleron. 



9i Petri: 6f; ein bajonettahnliches , gedrehtes Knorpelstvick > (p. 313); Moreau: Cartilage en hallebarde (Du- 

 vernoy I, no. 6. 



