ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 679 



— a gonosome— bears the sexual elements in its summit ; the hydro- 

 caulus is marked with many wavy bands visible from the surface, and 

 possesses a thin sheath with filamentous appendages at its lowest end. 



Medusae from the Tortugas.* — Mr. A. G. Mayer finds that there 

 is at the Tortugas, Florida, a tropical Medusan fauna, only three species 

 of which are established upon the southern coast of New England ; 

 and not one species of which is found upon the New England coast 

 north of Cape Cod. The Hydromedusaa of the Tortugas are more 

 closely related to those of the Fiji Islands, South Pacific, than they are 

 to those of the Canary Islands, off the Atlantic Coast of Africa. The 

 Leptoline forms of the Tortugas are almost wholly distinct from those 

 of the Canary Islands, but a number of Trachyline forms (which range 

 widely in the open ocean) are common to the two groups of islands. As 

 to the Siphonophorae, they are very closely related to those of the Canary 

 Islands, and also display a relationship to those of the Fiji Islands. 

 The Scyphomedusas are, for the most part, distinctly West Indian types, 

 and are not closely related to forms known from the African coast. 



The report includes 33 Hydromedusse, 3 Siphonophorse, 1 Hydroid, 

 and 2 Scyphomedusae, new to science, while 44 forms are new to 

 American waters. The following are especially noteworthy : — Pseudo- 

 clytia pentata, a hydromedusa normally pentamerous, " the survival 

 of a discontinuous meristic variation " ; Multioralis ovalis, a new 

 Hydromedusan with four separate manubria on a single straight chymi- 

 ferous canal which traverses the long diameter of the bell ; Eucheilota 

 paradoxa, the only known Leptomedusa which gives rise to tbe young 

 medusas by a direct process of budding ; Niobia dendrotentacula, a 

 Hydromedusan whose tentacles develope into medusas and are set free, 

 after which the adult reproduces sexually ; Bougainvillia niobe, in 

 which the medusa buds on the proboscis are entirely ectodermic ; 

 Oceania McCradyi Brooks, with bydroid-blastostyles on its gonads ; 

 and Dysmorphosa dubia, a Tubularian medusa, which seems to be unique 

 in having four rudimentary gonads (?) on the four radial canals. 



Atlantic Medusse.f — Mr. A. G. Mayer describes a number of new 

 species of Hydromedusse, a new Ctenophore of the genus Mnemiopsis, 

 and a new Scyphomedusan which forms the type of a new genus. The 

 last named, described as Bathyluca Solaris g. et sp. n., is believed to be 

 a deep sea form, but is known only from an injured specimen found at 

 the surface. The generic diagnosis is as follows : — " Discomedusaa with 

 a simple cruciform central mouth-opening, without mouth-arms or palps. 

 There are sixteen wide radial gastro-vascular pouches (eight ocular and 

 eight tentacular). There is no ring canal. There are eight marginal 

 sense-organs and sixteen marginal tentacles. There are four gonads 

 in the oral floor of the disc, and there are four sub-genital pits." The 

 paper is fully illustrated. 



Structure of Lucernaridae.J — Herr J. Gross discusses the differences 

 between Eleutherocarpidaa and Cleistocarpidae into which James Clark 

 divided the Lucernaridae. In the former there are four radial pouches 

 separated by septa ; in Cleistocarpidas there are eight, four outer and 



* Bull. Mus. Zool. Harvard, xxxvii. (1900) pp. 13-82 (44 pis.). 



f Tom. cit., pp. 1-9 (6 pis.). % Jena. Zeitschr. Naturwiss , xxxiii. (1900) pp. 611-23. 



