xcii THE VOYAGE OF H.M.S. CHALLENGER. 



or wholly the remains of the original four radial pouches of the coronal intestine, and the 

 centripetal septal ridges between them, as remains of the cathammal plates. 



§ 130. The marginal pouches of the Tesseroniae. It is only in the Tesseridae, the first 

 and oldest family of the Tesseroniae, that the peripheric coronal intestine is formed 

 exclusively of the four large perradial pouches and the marginal coronal canal or 

 coronal sinus, which connects the latter below the four interradial septa (Tesserantha, 

 PI. XV. figs. 2-6 ; Tessera, System, PL XXL). In all other Tesseroniae, other pouches 

 are found at the distal margin of the four perradial pouches, which are developed as 

 peripheric archings outwards of the latter and compose the corona of marginal pouches. 

 In the Lucernaridaa they are represented by four pair of arm pouches which pass into 

 the eight adradial arms or marginal lobes, from whose distal end they send out a tentacle 

 canal into each tentacle (Pis. XVI., XVII. ). The Charybdeidae, in which the eight 

 adradial marginal pouches are separated alternately by the four interradial septa and the 

 four perradial " frenula velarii " (PL XXVI. ), comport themselves quite in the same way. 

 In the Chirodropidae the number of radial pouches is doubled, as each of the eight 

 adradial marginal pouches is split up into two subradial lobe pouches (System, p. 446, 

 taf. xxvi.). In most Cubomedusae, moreover (with the exception of the lowest forms, 

 the Procharagmidaj) numerous simple or branched velar canals run out from the 

 distal margin of the lobe pouches, extend in the velarium (the broad marginal membrane 

 connecting the marginal lobes) and end caeeally with anastomosis (PL XXVI. fig. 8, cv). 

 The conditions differ somewhat in the Peromedusae, as in the Pericolpidae, first of all 

 (System, taf. xxiii.) eight principal coronal pouches (four perradial and four interradial) 

 run out from the distal margin of the coronal sinus. Their subumbral walls form the 

 eight coronal plates of the coronal muscle. Each of the eight coronal pouches is split up 

 into a medial principal canal, and two distal lobe canals. The medial canal passes into the 

 tentacle in the four perradial coronal pouches, into the sense clubs in the four interradial ; 

 whdst, on the other hand, the two lobe canals of each coronal pouch (bl) provide for the 

 halves of each two adjacent canals turned to each other, at whose distal end they 

 communicate by a horseshoe-shaped canal (bw) with the opposite canals of the other halves 

 (PL XXII. fig. 22 ; PI, XXIII. fig. 29). The Periphyllida? are only distinguished from 

 the Pericolpidas by having three tentacles with two intercalary subradial marginal lobes 

 in the place of each simple perradial tentacle (Pis. XVIII.-XXV). As the whole lobe 

 canals of the Peromedusa are connected below by U-shaped horseshoe canals (bn) at the 

 distal end of the marginal lobes, a waved connected festoon canal of pecidiar formation 

 is developed in all Peromedusae at the outermost margin of the lobed umbrella (PI. XX. 

 figs. 8, 22). 



§ 131. The marginal pouches of the Ephyronia?. Whilst in the Tesseronia? the 

 marginal pouches always appear as merely subordinate appendages on the distal margin 

 of the four perradial pouches (or of the large coronal sinus formed by junction of the 



