ON THE APPENDICES GENITALES (CLASPERS) IN THE GREENLAND SHARK. 



15 



«knee;> between the stem and the chief piece of the appendix (cf. fig. 58), in the most developed it 

 reaches ahnost half way towards the pelvis (cp. fig-. 60). As the glandular bag in most of the other 

 Sharks, which I have examined, reaches still further, generally even far beyond the pelvis, there is 

 reason to suppose that in none of the ventrals of the Greenland Shark in hand the whole copulatory 

 organ has reached the greatest development, which was already intimated by the description of the 

 skeleton of the terminal part. 



The connective tissue, investing the muscle-sheath of the glandular bag, is continued on all 

 the specimens as a very thin membrane between the skin and the ray-muscles almost to the pelvis; 

 this membrane may easily be separated as well from the skin as from the muscles, but in the 

 specimens in hand it (perhaps as a consequence of the preservation in brine) is very fragile; it contains 

 no striated muscular fibres. 



While the dorsal muscular wall of the glandular bag has no intimate couuectiou at all with 

 the part of the fin before the .knee — onh- a loose, soft connective tissue here joining the bag to 

 the ray-muscles — it is otherwise at the proximal end of the chief piece, part of the nuiscles of the 

 bag being inserted on the lateral surface of this part of the skeleton, covering it whoUv, and following 

 it quite down to the terminal part; other fibres attach to the last ray along its medial edge; and 

 some fibres arising from this spot and from the ventral surface of the two last rays, pass into the 

 dorsal muscular wall of the glandular bag and continue it to the ventral marginal cartilage, where 

 the>- attach to the connective tissue of its inner side. 



The direction of the fibres of the dorsal nmscular wall of the bag otherwise corresponds to 

 that in the ventral wall; as shown in fig. 60, the fibres radiate from the point, where the connection 

 with the skeleton anteriorly ceases; along the medial side they run almost in a parallel direction with 

 the axis of the bag and the appendage, but else on the broader part of the bag they spread in a 

 fanshaped manner to the lateral edge; on the hindmost narrow part they run entirely straight back- 

 ward, and here a few bundles pass into M. dilatator. This arrangement agrees very well with that, 

 which fibres originally directed from before backwards, might be supposed to get by being pressed out 

 of their position by an invagination protruding from the region between x x in fig. 60. A separation 

 of the muscular wall of the bag into two distinct layers is quite out of the question. With regard to 

 Acai/t/iias Petri (1. c. p. 316) has stated that the muscular wall of the bag consists of two layer.s, an 

 outer one of circular muscles, and an inner one of longitudinal muscles; a separation and arrangement 

 of such a kind however, is not found in ^icaiitliias. any more than in Spiiiax or the Greenland Shark. 

 Neither can I admit that the words of Petri (I.e. p- 317) are correct: Die Muskelschicht der Driise 

 wird nicht mit eingestiilpt, sondern sie differenzirt sich allmalich aus der Bindegewebsschicht nach 

 der Einstiilpung.x (Cp. also I.e. p. 328). In my opinion, as before has been shown, it admits of no 

 doubt that the muscles of the bag are simply borrowed from the original muscular system of the 

 skeleton'); in the earliest stages of Acanthias — male embryos of a length of 15'^'" — which I have 

 been able to e.Kamine in this respect, the muscles around the rudiment of the glandular bag are 

 alreadv as distinct as those surrounding the stem of the chief piece, and the muscular la}^er of 



■1 This is corroborated with p.irticular plainness by the arrangement in the Holocephales. 



