ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 63 



latter during the dilation acts especially on the terminal jDiece 7^, by which means this piece is turned 

 (revolving as the radius round the ulna in a human fore arm). 



The J/ compressor {S) forms the bag situated on the ventral side; the direction of its fibres, 

 as far as seen on the ventral side, is exacth' given on pi. VI, fig- 68; on the dorsal side (fig. 67) the 

 part forming the outer lip-muscle, which part is rather small, is seen anteriorly arising from the piece /?, 

 and posteriorly attaching itself in the inner investment of the ventral marginal cartilage; when the 

 connective tissue laterally uniting it with the hindmost ray, is prepared away, it is here very distinctly 

 seen to be continuoush- connected with the dorsal muscular wall of the bag'). 



The glandular body has by earlier authors been sufficiently described as well in this .species 

 as in other j'^^/rt'-species ; when developed it seems in all species to show principally the same 

 appearance. 



Raja radiata Donovan. 

 (PI. IV, fig. 53-57-) 

 Brief remarks on the appendices of this species are found in several authors, as usually mostly 

 concerning the size^) and the like facts. Lillj eborgJ),, however, not only says that they are very 

 large and in old individuals sometimes reach past the middle of the tail (in a specimen of the length 

 of 53'='" they were I4<^™ long and 3,2*^" broad on the middle), but he also gives a rather thorough de- 

 scription of their outer contour and whole shape; of the inner configuration of the appendix-slit he 

 only says that it is divided into parts or separate hollows >. He does not enter upon an examination 

 of the parts of the skeleton; he mentions only, that a piece in the dorsal lip has a free, backward 

 directed point. We find, however, in the older literature a representation of the skeletal parts of these 

 organs, as well as of their structure upon the whole, viz. by M. E. Bloch4). His specimen had a 

 length of 16 inch, (about 42'^'"), and the appendices (from the peh-is) were 572 inch, (abt 15''") long, 

 I'/s inch, (abt 3,5'"") broad across the terminal part. 



M Petri has called this part of my M. compressof M. flexor ptcyygopoil it biceps (I.e. fig. 2 B, flb), and thereby in- 

 dicated tliat he thinks it to be corresponding to the muscle in Scy/iium marked with the same name, which latter, however, 

 shows quite other relations (see my fig. 65 and 66 of Sc. s/e//are)\ he describes it as inserting itself on the dorsal marginal 

 cartilage instead of on the ventral one (this, perhaps, is only a miswriting). In the proximal part tlie Flexor pterygopodn 

 exterior of Petri corresponds to my M. adductor (A), his Flexor pt. interior to my M. extensor (E). The muscles men- 

 tioned by- Duvernoy (in Cuvier's Lemons 2d ed. vol.8, p. 307) are: i) Le muscle abaisseur = my Af. adductor; 3) L'abduc- 

 teur de I'appendice = M. extensor; 5) Le grand abducteur ou extenseur des pieces mobiles et terminales = M. dilatator; his 

 no. 2 le releveur de la nageoire» is the muscular layer coming from the body (pi. VI, fig. 67), and his no. 4 (Moreau's «court 

 extenseur ) I am unable to unravel. The same names have mostly been used by Moreau (I.e. p. 255); his Muscle long 

 extenseur = M. extensor, his M. flechisseur = the part of M. compressor forming tlie outer lip-muscle. Moreau, in 

 correspondence with my opinion, describes his M. grand abducteur {M. dilatator^ as separating into two bundles. Vogt & 

 Pappenheim, besides the already mentioned - ecarteurs > \M. dilatator) only mention the M. adductor as 'I'abaisseur de 

 I'appareil copulateur>, and as the antagonist of this a «releveur» partly formed by the dorsal muscular layer coming from 

 the body. Bloch only mentions two muscles in Raja radiata (I.e. vol.6, 1785) both together representing my M. dilatator. 



-j Kroyer I.e. p. 943 gives the measures: a specimen 171/2 inch, long with appendices of tlie length of 4' 2 inch., 

 and thinks (p. 9541 that the appendages are ver}' stronglj- developed in the adult males. 



3) 1. c. p. 552. 



4) Von den vermeinten doppelten Zeugungsgliedern der Rochen und Haie. Schr. d. Berl. Ges. naturf. Freunde, vol. 6, 

 17S5, p. 377- Bloch calls his Ra3--species Raja clavala L, and in his faunal works he has drawn and described it as Raja. 

 clavala. The figures, 1. c. pi. IX, however, show with perfect certainty that the species in question is R. radiata. (Both this 

 plate and the one concerning Acanthias are, without any explanation, affixed to the edition by Schneider of Bloch's 

 Ichthyology.) Petri has not perceived that in Bloch the question is not of the real R. clavala. 



