REPORT ON THE DEEP-SEA MEDUSAE. xcix 



the principal intestine, and of the coronal intestine, and even in the peripheric coronal 

 pouches. Chrysaora is usually purely male in youth, hermaphrodite later on, and purely 

 female when mature ; it seems, however, also to furnish purely gonochoristic specimens, 

 which during their whole lifetime form purely male or purely female sexual cells. 

 Hermaphroditism simUar to that of Chrysaora seems also to exist in the closely allied 

 Linergidas ; the peculiar, regularly distributed subumbral vesicles of these CannostomaB 

 appear to develop spermatozoa, whilst their genitalia only produce ova (System, p. 493, taf. 

 xxix.). Among the Craspedotse part of the Narcomedusse appear to be hermaphrodite ; 

 these and some other (probable) cases of hermaphroditism are not known with sufficient 

 certainty. The sperm cells of the Medusae are universally fine flagellate cells, not strik- 

 ingly distinguishable from those of other Acalephse. The egg cells are usually naked and 

 amoeboid in the Craspedotse (PI. I. fig. 8) but usually enclosed in fulcral capsules in the 

 Acraspedse (PL XX. fig. 7) ; in some Acraspedse they contain a visible food-yolk and 

 then come to more than 1 mm. in size (PI. XXV. fig. 4). 



§ 139. Genitalia of the Craspedotse. The reproductive glands are developed in all 

 Craspedotse (in thorough and important contrast to the Acraspedse) from the ectoderm of 

 the subumbral wall of the gastrovascular system, and when mature, are emptied 

 immediately into the umbrella cavity. They are sometimes formed more in the central 

 part of the gastrovascular system, sometimes more in the peripheric part ; in the first 

 case we call them gastral genitalia, in the second case, vascular genitalia. Gastral 

 genitalia in the subumbral wall of the central stomach, and the oesophagus proceeding 

 from it, are found in the two orders of the Anthomedusae (PI. I.), and the Narcomedusse 

 (Pis. X.-XIL), whilst on the other hand, the two orders of the Leptomedusse (PL II.), and 

 the Trachomedusse (Pis. III. -VIII.) have vascular genitalia in the subumbral walls of the 

 peripheric radial canals. There are, however, isolated exceptions in both groups ; the 

 central gastral genitalia sometimes grow centripetally and extend from the stomach also 

 on to the peripheric canals (e.g., Nemopsis among the Anthornedusae, System, taf. v. 

 figs. 6-9) ; in many they even pass mostly or entirely on to the gastral pouches of this 

 order, which originate from the proximal part of the radial canals (Pis. IX., XIII., XIV.). 

 In other cases the reverse occurs, and the peripheric vascular genitalia extend upon the 

 central stomach (e.g., Staurostoma, Staurophora, Orchistoma among the Leptomedusse, 

 System, taf. viii. fig. 6 ; taf. xv. figs. 3-5). If we consider the Craspedotse to be a 

 monophyletic group of animals, the gastral production of the genitalia may probably be 

 regarded in general as the older and original condition from which the vascular 

 production of the reproductive glands has been developed later, or we may assume that 

 the subumbral wall of the entire gastrovascular system originally produced sexual cells, 

 and that these productions were distributed later on the principal intestine and coronal 

 intestine. If on the contrary (and with more probability) we consider the Craspedotse 

 as a polyphyletic group, the vascular genitalia and the gastral genitalia may have arisen 

 in the different orders, independently of one another. 



