208 P. W. GAMBLE, B.SC. 



to elucidate. Personally I have found young specimens (*5 — 1 mm. 

 in length) fairly intelligible. In these the yolk-glands form finger- 

 shaped masses extending from the base of the pharynx to the genital 

 pore. In the adult they become reticular and very bulky. The 

 elongate, narrow germaria consist of a single row of ova for the greater 

 part of their length. Behind their point of union is the large 

 spermotheca. All these organs, the yolk-germ-glands and spermotheca, 

 open into a single female genital canal. This canal is chitinised 

 internally, and leads to the genital atrium. For an account of the 

 male gonads with figures see v. Graff, ' Monographie,' pp. 330-1, pi. ix ; 

 and Jensen, ' Turbellaria Norvegise.' pi. iv. The most important fact 

 is that in addition to a chitinous sheath for the " graDule-secretion," 

 there is a common one for both this and the terminal vas deferens 

 (see v. Graff, 'Monogr.,' p. 166, woodcut, fig. 9, G.). The poison-organ 

 consists of a hollow chitinous stylet 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. Graff) ; 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 (Meresch- 

 kowsky, 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 conspicuous 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. 

 Acrorhynchince 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). 



