1908.] ANATOMY OF A FROG. 37 



opposite to, those integumental sheets. The resemblance of the 

 extrinsic muscles of the heart to the " cdce cordis " of the Arthro- 

 pod heart is thus increased, since there is (or at least may be) a 

 pull on each side in opposite directions which would clearly dilate 

 the cavity of the lymph-heart. The contraction of the heart is 

 probably effected by the intrinsic musculature. This muscle, 

 when the heart is viewed from the dorsal surface as in text- 

 fig. 11, is seen to reach the heart as two broad flat bands which 

 fan out over its dorsal surface. They are seen to dip down 

 ventrally between the heart and the ilium, and to unite to form 

 one stout strap-shaped band of muscle. The position of this 

 muscle is exactly on a level with the tip of the coccyx, and there 

 is an exact symmetry between the two of opposite sides of the 

 body. It is inserted on to the symphysis pubis. 



In addition to the muscles just mentioned, which are indicated 

 in text-fig. 4 (p. 20), and shown more in detail in a more enlarged 

 representation of this region of the body (text-fig. 11), there is 

 another muscle attached to each lymph-heart more ventrally than 

 that which has just been described. This completes the mooring 

 of the lymph-hearts to the adjacent organs of the body. The 

 muscle now under considei'ation is single on each side of the body ; 

 that is to say, there is one of them to each lymph-heart. It is 

 broad and flat and thin, and shows a metallic glitter on account 

 of its structure; it arises in the neighboin^iood of the edge of 

 the expanded transverse process of the sacral vertebra, and 

 thus partly covers over and conceals the coccygeo-sacralis muscle. 

 The course is backwards, and it i-eaches the first described skeletal 

 muscle of the lymph-heart at right angles to that muscle. It 

 dips under it, a,nd is therefore attached to the lymph-heart rather 

 ventrally. The muscle is broader than that which runs from the 

 pubis to the Ijanph-heart, but could be readily missed owing to 

 its tenderness and the consequent ease with which it can be 

 torn *. 



§ Organs of Beproduction. 



I have had the opportunity of examining both sexes of this frog, 

 as has already been mentioned in relation to the alimentary system. 

 In the male (text-fig. 13), the testes have the usual oval form and 

 are not pigmented. From their considerable size, I gather that the 

 individual was sexually mature. They lie very close together and 

 actually indeed in contact, the mesocolon only just being able to 

 pvish itself between them, as it were. Nor can they be separated 

 by any manipulation short of forcibly tearing them away from 

 the dorsal mesentery which attaches them and the colon to the 

 middle dorsal line. The vasa efferentia seem to ofier a new 

 form of these ducts among the Anura. There is only a single 



* The appearance of the lymph-heart is by no means unlike that of the Tortoise as 

 represented by Fritsch, " Zur Auatomie der Elephant-Schildkrote {TesUido ele- 

 phantopus)," Prag 1870, from Abh. k. bohm. Ges. Wiss. 1871. 



