724 Leuckart: Bericht üb. d. wissenschaftlichen Leistungen 



kümmerung gebracht. Daneben trifft man nicht selten 

 noch andere Parasiten , wie das zum Theil schon von 

 frühern Beobachtern angemerkt wurde. So besonders eine 

 Aphroditee und eine Nemertinenform, die beide vorzugs- 

 weise die jüngeren Zweige bewohnen und an diesen man- 

 cherlei abnorme Bildungen hervorrufen. 



Die ausführlichere Darstellung in deii Philos. Trans- 

 actions enthält (pag. 473 ff.) neben der Anatomie der vom 

 Verf. beobachteten einzelnen Formen noch einen syste- 

 matischen Theil, in welchem Moseley die einzelnen 

 Genera auf Grund seiner Untersuchungen neu charakteri- 

 sirt — zwei derselben werden nur kurz, in einem Post- 

 script, behandelt — , sodann die dahin gehörenden Arten 

 aufzählt und schliesslich den Versuch macht, die verschie- 

 denen Formen genealogisch aus einander zu entwickeln. 

 Wir entnehmen diesem Theile zur Vervollständigung unse- 

 res Berichtes die nachfolgenden Diagnosen. 



Sabord. Hydrocorallinae. Compound hydroid Stocks growing 

 by gemmation. Hydrophyton consisting of a meshwork of ramified 

 coenosarcal canals, composed of an ectoderm and pigmented endo- 

 derm, lodged within Channels permeating a hard calcareous support 

 (corallum) which is deposited by the ectodermal investment of the 

 canals and forms masses of very various shape- Surface of the 

 hydrophyton covered with a continuous layer of ectoderm. Zooids 

 of two forms, the one provided with a mouth and gastric cavity 

 (gastrozooid), the other mouthless and simple tentaculae in function 

 (dactylozooid). Tentacles, when present, mostly with knobbed extre- 

 mities. A well-defined muscular layer present in the zooids. Zooids 

 lodged within Chambers excavated in the substance of the hydro- 

 phyton (gastropores and dactylopores), lined by reflections of the 

 surface layer of the ectoderm, forming the sacs of the zooids. Zooids 

 of the two forms either scattered irregularly over the surface of the 

 stock, or gathered into groups more or less regulär, in each of 

 which a centrally-placed gastrozooid is surrouuded by a riog of 

 dactylozooids. Cavities of zooids communicating with coenosarcal 

 meshwork by large canal ofFsets. 



Farn. Milleiioridae. Corallum irregulär in growth, arborescent 

 or incrusting, composed of a thin superficial living layer, supported 

 by a dead mass made up of succession preceding dead layers. 

 Pores devoid of styles, divided into a series of vertically succeeding 

 Chambers by transverse calcareous partitions (tabulae). Usually scatte- 

 red irregularly, but in some species grouped with tolerably regu- 



