Miscellaneous. 407 



towards the coming investigations. In the present note therefore 

 I shall enumerate the forms captured in our bay in gradually de- 

 Bcending from the shore to a depth of 200 metres. 



A. Littoral Zone, indiuUng the Meadows of Posidonia Caulini. — 

 Although the Alcyouaria are not usually littoral animals, we find 

 three species pretty abundantly in the zone that fringes the shore 

 and extends to a depth of 20 metres. These littoral Alcyonjjria are 

 of small size, and belong to the family Cornialarinae. 



llJdzoxoiia rosea., Ph. sp. The corms of this species occur pretty 

 frequently attached to stones a few decimetres under water along 

 the shore of Cape Janet. They are also met with, but more rarely, 

 on the rhizomes of the Posidoiiice, at a depth of 15 metres, at some 

 points on the shore of the isle of Katonneau. 



Clavidaria crassa, M.-Edw. (Conmlaria crassa). The Cornnlaria 

 crassa figured in the * Regno Animal ' is a true Clavidaria without 

 any cuticular covering, but furnished, on the other hand, with an 

 abundance of sclerites. In the J3ay of Marseilles Clavidaria crassa 

 abounds on the rhizomes of the Fosidoiii(e of the creek of Ratonneau 

 at a depth of 2 or 3 metres. Some corms of the same species not 

 bearing more than three or four zooids, and presenting only a pale 

 tint, have been observed at much greater depths (110 metres) at- 

 tached to fragments of shells, beyond the bay, to the south of the 

 Isle of Riou. The reproduction of this species takes place in June. 

 The male colonies difier from the female in the length and sleuder- 

 ness of the polypes. The ova, enveloped in a rather dense mucus, 

 are borne at the extremity of the zooids, after the fashion of the 

 ova of Dasyclione Incidlana. It was upon this species that Kowa- 

 levsky and myself in 1S7U observed a very distinct total segmenta- 

 tion, the formation of a planula, and the histological differentiation 

 of an ectodermic pseudomesoderm, not passing through the stage of 

 a cellular blastodermic lamella. 



We have no zoological information as to the Neapolitan Clavidaria 

 named C. ochracea by Gr. von Koch (Morph. Jahrb. vii. livr. 3, 

 1881). This Alcyonarian perhaps does not differ from the one here 

 cited. 



Cornularia cornucopice. This species is easily recognizable by ita 

 little cornets secreted by the ectoderm, and resembling the protec- 

 tive tubes of the Tuhiporce. In the Ray of Marseilles it is associ- 

 ated with Clavidaria crassa; but it is always rarer, and does not 

 appear to quit the meadows of Zostera. 



B. Maddi/ and Sandij-muddy Zone bei/ond the Zosterte. — The 

 meadows of Posidonice are sometimes margined by mud or muddy 

 sand, sometimes by coralligenous gravels. The muddy spaces 

 abound particularly in the north-western region of the bay ; and 

 there the depths vary from 30 to 80 metres. The Alcyouaria hold 

 an imi)ortaut place in the fauna of these stations. 



Alci/oni urn 2)(ilmatiiyn, Vail. Very abundant. All the corms be- 

 lon"' to the typical form, the base of which is prodnccd into a long 

 peduncular stalk, destitute of zooids, and buried in the mud. It 

 was coUecU'd in the Ray of Riscay in 1880, 



