ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 303 



Molcjula citrina, Alder & Hancock. Low water, Lerwick, 1861. 



Cynthia coriacea, Alder & Hancock. Dourie Yoe, 1863. 



grossularia, Van Beneden. Common between tide-marks. 



. echinata, Linn. ; Ascidia echinata, Forbes & Hanley, vol. i. p. 35, pi. C. 



fig. 4. 5_4Q fathoms, Middle Haaf and Bressay Sound, 1863. Para- 

 sitic on Ascidia sordida, 5-8 miles east of Balta, 40--50 fathoms, 1867. 



Clavelina lepadiformis, Miiller. One mile north of Whalsey Lighthouse, 



Polydinum aurantium, M.-Edwards. 3-5 fathoms, Out Skerries Harbour. 



1 succineum, Alder, Ann. Nat. Hist. 1863, vol. xi. p. 169. The type spe- 

 cimen was dredged in 1861, in 50 fathoms, on the Haddock-ground, 6 

 miles north of Whalsey Lighthouse. 



Amarcecium albicans, M.-Edwards, Observ. sur les Ascidies Composees, p. 287, 

 pi. i. fig. 3 b. Low water, Lerwick. 



.? An undetermined species, tide-marks, Balta Sound, 1863. ^ 



Botnjllus and Botrylloides. About ten species observed, but not determined 

 satisfactorily. 



Leptodinum durum, M. -Edwards =Leptoclinum aureum (misprint), Forbes <fc 

 Hanley, vol. i. p. 17. Tide-marks, West Yoe, Out Skerries, 1861. 



punctatum, Forbes. With the last. 



Didemnum gelatinosum, M.-Edwards, Obs. Ascid.'Compos. p. 295, pi. vn. fig. 5. 

 Low water, spring tides, West Yoe, Out Skerries ; and in Out bkemes 

 Harbour, on roots of Laminaria3. 



Parascidia Flemingii, Alder, Ann. Nat. Hist. 1863, vol. xi. p. 172. Sidnyum 

 turbinatum, Fleming. Low water, Lerwick. In Mr. Alder's opinion this 

 is not the Sidnyum turbinatum of Savigny (Mem. Anim. sans Vertebres, 

 vol. ii. p. 238), nor the Sidnyum turbinatum of Forbes and Hanley, which 

 he also considers distinct from Savign/s species, and proposes to name 

 Parascidia Forbesii. 



Salpa runcinata, Chainisso. Both sexual and asexual forms in vast numbers 

 in company with Diphyes and Physophora, 30-35 miles, Is JN.W. or 

 Burrafirth Lighthouse, July 17 and 18, 1867. 



Appendicularia flagellum, Huxley. Some Appendiculance were taken by me 

 in the towing-net in Balta Sound in 1863, which I believe belonged to 

 this species ; but the bottle in which they were preserved was unfor- 

 tunately lost (I conclude left behind in Shetland), and thus also the 

 accurate determination of the species. 



Class POL YZO A. 



For this class I have adopted, as far as it goes, the general arrangement 

 of Mr. Busk, in ' A Monograph of the Fossil Polyzoa of the Crag, 1859.' 

 This work having been published subsequently to the ' Catalogue of Marine 

 Polyzoa in the collection of the British Museum, 1852,' gives us the author's 

 maturer views. With respect to the species, if no reference to other works 

 is given, they will be found described in the ' Catalogue;' but, as will be 

 seen by the following Report, our knowledge of the animals of this class has 

 been very materially extended since 1852. Herr F. A. Smitt has just pub- 

 lished a valuable series of papers on the Polyzoa of the Scandinavian seas, 

 entitled "Kritisk forteckning ofver Skandinaviens Hafs-Bryozoer" (OlVers. 

 af K. Yet.-Akad. Forhandl. 1865-67), but I am not prepared to acquiesce in 

 his views as to the amount of variation to be observed in species of 

 the class. 



