BEITISH MARINE TURBELLAEIA. 527 



of eye. M. Mouth. ME. Muscular envelope. MR. Mucous-rods. N. 

 Nucleus of epidermal cells. OT. Otolith. PA. Packets of rhabdites. PK 

 Penis. PH. Pharynx. BE. Rhabdites. RS. Receptaculum seminis. 

 SE. Spermatozoa. SP. Pharyngeal glands. TE. Testis. F. D. Vasa 

 deferentia. VG. Vesicula granulorum. VS. Vesicula seminalis. W. 

 Ciliated groove. 



PLATE XXXIX. 



Fig. 1. — Young Stylostomum variabile, Lang. Natural length 9 mm. 

 The three pairs of eyes placed over the brain are very conspicuous, and per- 

 sist in the adult (see p. 512). X 65. 



Fig. 2. — Cycloporus papillosus, var. Isevigatus, Lang. Natural size. 

 This form exhibits almost complete similarity in colour, form, and con- 

 sistency with the Ascidians on which it is usually found. 



Fig. 3. — Oligocladus sanguinolentus, Quatref. Length 1"1 cm. x6. 



Fig. 4. — Cylindrostoma inerme (Hallez). Length 1 mm. The draw- 

 ing is made from a specimen slightly compressed. Zeiss obj. C, oc. 4, cam. 

 luc. X 55. 



Fig. 5.— Macrorhynchus Naegelii, K611. Lengtji 2-2 mm. This is a 

 colour variety similar to what Claparede observed at St. Vaaste (see p. 462). 

 X 30. 



Fig. 6.— Promesostoma lenticulatum (0. Sch.). Natural length -5 mm. 

 The carmine-coloured gut is visible. X 100. 



Fig. 7. — Enterostoma austriacum, Grff. Natural length 75 mm. 

 The yellow colour is due to groups of pigment-granules, the black spot to 

 the contents of the intestine, x 40. 



Fig. 8.— Provortex rubrobacillus, n. sp. Natural length -6 mm. The 

 brown spots are due to the contents of the gut-cells. X 70. 



Fig. 9.— Fovia affinis (Oe.) (probably Uteriporus vulgaris, Bergen- 

 tal). Natural length 4-5 mm. The figure is carefully drawn from a 

 freely-moving specimen. The slight lobes of the anterior margin are seen 

 when the animal is viewed from below and in front ; this view also shows a 

 slight median projection — similar, in fact, to what occurs inConvoluta para- 

 doxa. X 8. 



Fig. 10. — Promesostoma marmoratum (Schultze). Natural length 

 1-5 mm. X 20. 



