BRITISH MARINE TTJRBELLARIA. 465 



enclosed at its proximal end by a muscular sheath containing 

 the poison-glands. A strong retractor muscle passes from the 

 blind end of this muscular sheath, and is inserted on the upper 

 end of the granule-reservoir. 



Habitat. — At the commencement of the Laminarian zone, 

 Millport (v. GraflF) ; Plymouth ; Port Erin, Isle of Man (F. 

 W. G.). Young specimens abounded at the last locality in 

 October, 1892. 



Distribution. — West Greenland (Levinsen), White Sea 

 (Mereschkowsky, 48), Bergen (Jensen), Wimmereux (Hallez). 



A most remarkable character of the Proboscidae, as a family, 

 is the discontinuity of the gut caused by the development of 

 the various genital organs, and in no form is this more con- 

 spicuous than in Macrorhyncus heligolandicus. In young 

 specimens the gut is a closed sac surrounded by the body- 

 cavity. As the gonads develop, becoming more and more 

 bulky, the gut gets squeezed into any unoccupied spaces. 

 Thus the gut-cells become scattered, and accumulate chiefly 

 along the mid-dorsal surface. This fact accounts for the 

 absence of a definite intestine in adult specimens. 



Genus 14. — Gyrator, Ehrbg., 1831. 



Acrorhynchinse with two genital pores, of which 

 the female is the anterior. Germarium single; 

 testes elongate. Vesicula seminalis and granule- 

 reservoir separate, the latter with a special 

 chitinous duct (v. Graff, ' Monogr.,^ p. 331). 



25. Gyrator hermaphroditus, Ehrbg. (10). 



1875. Prostoma lineare, Mcintosh (45). 

 1879. „ „ Hallez (50). 



Details of Mclntosli^s specimens are not given. I append 

 the following ol»servations which I have made on specimens 

 taken in the neighbourhood of Manchester. 



