OCR Text |
Show 1903.] FROM ZANZIBAR AND BRITISH EAST AFRICA. 103 between them is occupied by a loose spongy reticulum of protoplasm with few nuclei. At its proximal end the penis receives the very short duct which opens into it from the prostate {pr.), which with its duct is ensheathed in a continuation of the muscle-wall of the penis, which at this level again fuses with the muscles of the outer sheath. Text-fig. 3. Sketch of anatomy of Paraplanocera aurora, sp. nov. a.v., accessory vesicle; br., brain; b.c, bursa copulatrix ; m., mouth ; p., penis; pr., prostate; v.d., vas deferens; v.s., vesicula seminalis; t., tentacle. The prostate is large. There is a pair of thin-walled vesiculae seminales {v.s.) outside the sheath. From each of these a short duct runs, piercing the sheath, and uniting with its fellow to enter the commencement of the prostatic duct. The terminal parts of the female apparatus are exactly similar to those of P. langi, structurally and histologically. However, in the present species I cannot find any indications of the shell-glands. DISPAROPLANA DUBIA, gen. et sp. nov. (Plate IX. fig. 2.) A single specimen. Length 12-5 mm. Breadth 3"0 ,, " Mouth " from anterior end 4"0 „ <3 aperture from " mouth " T5 ,, $ „ 11 male -4 „ The external characters of this species are shown in text-fig. (p. 104). There are no tentacles The eye-spots are arranged in two |