72 OLWEN M. KEES. 



External Characters of E. mazeli (Jourdan). 

 The following description of the external characters of E. mazeli 

 (Jourdan) is based on an examination of a preserved specimen from 

 Naples. Length of scapus, 47 mm. ; it tapers gradually downwards. 

 Diameter at summit of scapus, 11 mm. ; diameter at base, 7 mm. The 

 base, which is slightly enlarged, is very similar to that of Peachia, being 

 invected somewhat in the centre to a depth of several mm. Upper 

 margin well demarcated, surface of scapus without tubercles, but very 

 much folded and wrinkled and thrown into numerous complex ridges. 

 Tentacles, 20 in two alternating cycles of 10 each, the outer the longer. 

 In this specimen they are contracted, rather stout, tapering slightly 

 upwards and then expanding into a globular or ovate head. Length of 

 outer tentacles 10 mm., inner 4 or 5 mm. Colour, greenish white (in 

 spirit). The tentacles are mottled with dark purplish brown blotches. 

 These become larger and confluent higher up, and in the contracted 

 tentacles appear as slightly raised vesicles or blisters. On the head 

 of the tentacle these marks are of a paler brown suggestive of a less de- 

 gree of contractility. The disk is narrow and concave ; the mouth 

 pointed and prominent. 



Internal Structure of the Italian Specimen of E. mazeli. 



The mesenteries are twenty in number, and are all perfect and fully 

 developed. Their arrangement is very simple, the mesenteries arising 

 in pairs and two of these pairs are directives (Fig. 1). The longitudinal 

 muscles of each pair are on the faces which look towards the intra- 

 mesenterial spaces, except in the case of the four directive mesenteries 

 whose longitudinal muscles are on the faces which are turned towards 

 the adjacent intermesenterial spaces. There is only one siphonoglyphe, 

 and this is deep and well defined. The surface of the stomatodseum 

 possesses numerous ridges which increase the digestive area. The body 

 wall consists of ectoderm, mesoderm, and endoderm in almost equal 

 proportions. The ectoderm has a corrugated appearance on its outer 

 surface owing to the body wall being slightly contracted. The mesogloea 

 is fibrillar, especially towards the inner surface, as in Halcurias. 



Jourdan, in his description of the internal characters of Eloactis, also 

 shows the fibrillar nature of the mesoderm : " Sur les coupes transversales 

 le picrocarmin colore vivement le mesoderme et permet d'y distinguer 

 deux zones, I'externe composee de tissu conjonctif lache, I'interne formee 

 de tissus lamineux"("In transverse sections, the mesogloea is deeply stained 



