252 



the same size as the pelagic egg of P. platessa: the volume of yolk 

 indeed is somewhat less. The former takes between three and four 

 Meeks to hatch, the larva is about 7,5 mm in length, has the mouth 

 open, and is well developed; at the same mean temperature the latter 

 hatches in about 16 days, the larva is 4,1 mm long, the mouth is not 

 formed, and it is ill- developed. 



It also explains the gradual, prolonged spawning. From the final 

 distension of the ovum, the female is unable to carry simultaneously 

 all the eggs in the mature condition ; but the expansion takes place 

 sporadically throughout the ovary , a comparatively small number 

 undergoing the change and being expelled at one time. The gross 

 volume of the eggs shed in one season may considerably exceed the 

 volume of the body of the female. Thus a large flounder [P. flesus) 

 examined a little before the spawning season had a volume of 951 ccm, 

 the ovaries occupying 170 ccm and the body 781 ccm; the number of 

 opaque eggs present was computed to be 2,733,800, with a volume in 

 the mature condition of about 1114 ccm, of which nearly two-thirds is 

 water. 



Edinburgh, February 28th 1898. 



4. Neue Turbeliarien der Bucht von Concarneau (Finistère). 



(Vorläufige Mittheilung.) 

 Von Dr. O. Fuhrmann, Académie, Neuchâtel. 



eingeg. 8. März 1897. 



Während eines Aufenthaltes an der Zoologischen Station von 

 Concarneau beschäftigte ich mich speciell mit der überaus reichen 

 Turbellarienfauna der so thierreichen Meeresbucht. Ich fand 29 Arten, 

 worunter 5 neu sind. Damit ist aber die Zahl der Turbellarienarten 

 noch nicht erschöpft, denn es kamen mir noch mehrere Formen zu 

 Gesicht, die ich wegen Mangel an Material oder aus anderen Gründen 

 nicht bestimmen konnte. 



Die gefundenen sind folgende : 



Proporus venosus O. Seh.; Convoluta flavihacillum Jens.; C. para- 

 doxa Oe.; Macrostoma hysirix Oe.; Microstoma ruhromaculatum Graff, 

 Microstoma lucidum nov. spec. ; Stenostoma Sieholdii Graff; Prome- 

 sostoma marmoratum Graff; P. ovoideum Graff; Proxénètes ßahellif er 

 Jens.; P. gracilis Graff; Acrorhynchus calédoniens Graff; Macrorhynchus 

 helgolafidicîis Graff, M. iVaye/« Graff, 31acror/iynchus coeruleus nov. spec; 

 Hyporhynchus setigerus Graff, H. penicillatus Graff; Provortex halticus 

 Graff; Plagiostoma Fahrei nov. spec, Plagiostoma molaceum nov. spec, 

 P. dioicum Graff, P. Girardi Graff, var. major Böhmig, P. vittatum 



