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Show 1903.] ON THE ANATOMY OF A NEW GEPHYREAN WORM. 29 P l a t e I II . Fig. 1. Barbus prngenijs, p. 24, f . 2. Barbus batesii, p. 25, P l a t e IV . %Iicrosy)iodontis batesii, p. 26. a. The whole fish, natural size. b. Mouth, X 2. c. Skeleton, natural size. d. Upper view of skull, shoulder-girdle, and nuchal shield, X 1£. e. Side view showing air-bladder and anterior part of vertebral column, X 2. f. Left transverse processes of coalescent anterior vertebra), X 3. P l a t e V. Fig. 1. Anabas pleurostigma, p. 27, y. 2. Mastacembelus sclateri, p. 28, natural size. 4. On the Anatomy of the Gephyrean Phascolosoma teres, n. sp. By W . K. H u t t o n , M.A., M.B., Senior Demonstrator of Anatomy in the University of Glasgow. [Received November 6, 1902.] (Plates V I .-V I I I .1 & Text-figure 9.) Some time ago, while engaged in dredging-operations in the Firth of Clyde, Dr. J. F. Gemmill obtained two specimens of the Gephyrean worm figured in Plate VI. fig. 1. These he handed over to me, and at his suggestion I undertook the task of identifying them. My examination having led me to the conclusion that I was dealing with an animal hitherto undescribed, it seemed advisable to give some account of its anatomy ; and this I have essayed to do in the following pages. Unfortunately the presence of sand in the alimentary tract, no less than the leathery nature of the animal's skin, formed an almost insuperable obstacle in the way of obtaining continuous series of sections: as a result, my account is in some respects incomplete. The worm was dredged from a depth of 60 fathoms, nine miles to the south-west of the Corsewall Light. The bottom was fine mud. External Characters and Integument. The worm is shaped like a very long-necked Florence oil-fiask and measures 4-0 mm. in length. Since, however, in both individuals examined the introvert was almost completely invaginated, in order to estimate the true length probably 8 mm. must be added to this figure. The body of the worm is seen (Plate V I. fig. 2) to consist of three portions which differ externally, and are found upon dissection to have definite relations to the contained viscera. First, occupying the anterior third or more of the animal's 1 For explanation of the Plates, see p. 40. |